The field of the present invention is mechanisms for controlling and transmitting rotational motion and power.
Mechanisms for controlling rotational output using a fluid as a force transmitting means have been widely used as fluid couplings. Other designs are known where pumps generate fluid pressure and flow which is then converted to rotational output through fluid motors. Continuously variable ratios are even possible with some systems.
A difficulty with the use of fluid for power transmission is that fluid flow can introduce substantial inefficiencies to such systems. Efforts have been made to reduce such losses by increasing the pressure with a corresponding decrease in flow rate. However, by increasing the pressure, leakage and/or cost can become a significant factor.
Techniques are also known for mechanically locking up couplings once velocities across the coupling are matched. By augmenting the system with a mechanical lock, fluid losses can be greatly reduced.
Gear pumps are also well known. Such pumps typically include a gear set. An inlet provides fluid in the area of the pinch where the gear wheels are separating. An outlet is provided to the other side of the pinch where the gear wheels are coming into engagement. Such pumps are frequently used for system lubrication and the like.